(19)
(11) EP 2 511 774 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
20.08.2014 Bulletin 2014/34

(43) Date of publication A2:
17.10.2012 Bulletin 2012/42

(21) Application number: 12153294.9

(22) Date of filing: 31.01.2012
(51) International Patent Classification (IPC): 
G03G 15/23(2006.01)
G03G 21/00(2006.01)
 G03G 15/01(2006.01)
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(30) Priority: 01.02.2011 JP 2011019880

(71) Applicant: Miyakoshi Printing Machinery Co., Ltd.
Narashino-shi Chiba 275-0016 (JP)

(72) Inventors:
  • Izawa, Hideo
    Narashino-shi, Chiba 275-0016 (JP)
  • Takahashi, Kenji
    Narashino-shi, Chiba 275-0016 (JP)
  • Setoyama, Junichi
    Narashino-shi, Chiba 275-0016 (JP)

(74) Representative: Office Freylinger 
P.O. Box 48
8001 Strassen
8001 Strassen (LU)

   


(54) Sheet-fed duplex and sheet-fed duplex multi-color printers


(57) To allow shortening the horizontal length for sheet-fed duplex printing while preventing a printing face of the sheet of paper printed on upstream in its conveyance direction from becoming soiled by toner transferred from a printing face of sheet of paper printed on downstream in its conveyance direction, a sheet-fed duplex printer comprises a pair of impression cylinders 6a, 6b each provided on a peripheral surface thereof with a paper gripper for gripping a sheet of paper, one of the impression cylinders in rotational contact with the other impression cylinder disposed downstream in a direction of rotation of and obliquely below the one impression cylinder. The two impression cylinders are synchronously rotated so that the regions of rotational contact thereof both move downwards. The sheet of paper reversing its printing face when the sheet of paper conveyed following a peripheral surface of the one impression cylinder is conveyed to follow that of the other impression cylinder. A first electrophotographic printing unit 7a is disposed opposite to a peripheral surface area of the one impression cylinder which area is upstream in the direction of rotation of the one impression cylinder from the region of rotational contact between the one and the other impression cylinder for printing on one face of the sheet of paper being conveyed following the peripheral surface of the one impression cylinder. A second electrophotographic printing unit 7b is disposed opposite to a peripheral surface area of the other impression cylinder which area is downstream in the direction of rotation of the other impression cylinder from the region of rotational contact between the one and the other impression cylinder for printing on the other face of the sheet of paper being conveyed following the peripheral surface of the other impression cylinder. And, a cleaning unit 23 for impression cylinder is disposed opposite to, and adapted to clean, a peripheral surface area of the other impression cylinder, the peripheral surface area of the other impression cylinder being downstream in the direction of its rotation from a position thereon at which the sheet of paper conveyed following the surface of the other -impression cylinder is transferred therefrom downstream in the direction of conveyance of the sheet of paper.







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